Microadjusting device



sept. 3, 1929. C, R, BUTLER 1,727,098

- MICRO ADJUSTING DEVICE Filed Nov. 18, 1922 N VEN TOR. ar//J if 9a/If;

ATTO Y Patented Sept. 3, 1929.

CHARLES n. BUTLER., or INDIANAroLis, INDIANA.

MICROADJ'USTING DEVICE.

Application led November 18, 1922; Serial No. 601,903.

lIt is the object of my invention to provide a simple and effective adjusting device for readily getting both coarse and fine angular adjustments of a shaft, to get both adjustments without lost motion, and to get these results by aV device which is inexpensive to manufacture and which is smooth inoperation.

In carrying out `my two concentric adjusting members, one o which is rigid with the shaft to be adjusted ,and the other of which carries a cam, and I provide means operated by the cam to vary the position of the member rigid with the shaft relative to a third member, such third member being spring-pressed against a stationary part so that it may remain stationary` during adjustment of the shaft by the cam-carrying member but may turny with the shaft during adjustment by the other adjusting member.

I have illustrated my invention in connection with a variable condenser of the type much used in radio receiving sets; but my adjusting mechanism is capable of many other uses.

The accompanying drawing illustrates my invention: Fig. 1 is a side elevation in partial section on the line 1-1 of Fig. 2, showing my device applied to a condenser mounted on the usual panel of /a radio receiving set; Fig. 2 is a front elevation -in artial section on the line 2--2 of Fig. 1.; ig. 3 is a invention I .provide rear elevation, with the shaft in section;

Fig.I 4 is a section on the line 4-4 of Fig. 3; Fig. 5 is a section similar to Fig. 1, showing a modification; Fig. Gis an enlarged view o the central portion of Fig. 5; and Fig. 7 lis a rear elevation of the modification of Fig. 5. l

The variable condenser 10, in connection with which I have shown my invention, may be mounted upon a panel board 11. This condenser has the usual stationary plates 12 and movable plates 13, the latter being mounted on a shaft 14.

A graduated disk 15, having a hub 16, is fixed on the shaft, as by a set-screw17. knob 18 isloosely mounted on the hub-16 and is capable of rotary movement relative thereto but prevented from longitudinal movement. by a screw 19, the end of which fits in an annular groove in the hub 16. The disk 15 is manipulated for coarse vadjustment, and the knob 18 for fine adjustment.

A cam 21, ri 'd with the knob 18, as by being molded integral therewith, pro'ec'ts 1nto a circular recess in the outer face o the disk 15, in position to operate a cam-follower f short shaft 23, displaced from but parallel to the main shaft 14 of the condenser and carriedby and extending through the disk 15, and having an arm 24 on its other end. Thus the cam-follower 22, shaft 23, and arm 24 constitute a bell-crank in which the twoy arms lie in separate parallel planes.

Now referring specifically to the arrangement shown in Figs. 1 to 4 inclusive, a spider 25 ofy spring material is mounted on the inner end of the hub k16 and is free to rotate relatively thereto. I preferably provide a oove on the inner end orf the hub 16 into w ich ma be snapped a spring-wire rlng 26, to hol 'the spider 25 in place relative to the disk 15 when the device as a whole 1s not mounted on the shaft 14; but the spr1ngwire ring is notv at all essential to the operation of the device. The spider 25 `shown is provided with three legs which bear against the face of a stationary member, such as the panel board 11, but the number of legs is of course, immaterial. The spider is also provided with a triangular shaped arm 27, the Haring edges of which are bent to extend on both sides of the arm 24. I prefer to bevel the. sides of the arm f 24 and bend the edges of the arm 27 to fit this bevel as shownr in Fig. 4, in order to counteract any tendency of the arm 27 to ride over the arm 24. The outer end of the arm 24 has a fulcrum in the narrow' outer end of the arm l27, and the flare of the sides of the arm 27 permits the arm 24 to swing therein about such fulcrum. A spring 28 has one end bent laterally and inserted 1n a hole in the disk 15. Fromjthis point the spring encircles the shaft 14, and at its other A end extends through. a hole in an arm 25 of the spider 25. This spring serves to hold the cam follower 22 against. the cam 21, as its action is transmitted through the spider 25, arm 24, and shaft 23 to the cam follower 22. As shown in Fig. 2, this s ring tends to turn the spider counter-clockwise relatively to the disk 15. As the spring holds the cam follower in contact with the cam at all times, there can be no lost motion in the operation of my invention. This particular form of spring is not essential to my invention, and any spring serving the same purpose may be substituted therefor.

I provide a stop pin 29 on the disk 15 and a co-operating stop pin 30 on the knob 18. These pins are so located relative to the disk and knob that they prevent turning of the knob relative to the disk past the point where the cam follower would drop from the higher part of the cam to the lower part.

In the modification of my device shown in Figs. 5, 6, and 7, I provide instead of the spider 25 a disk 33 spring-pressed at its edge against a stationary member, such as the panel board 11, as by means of a coil spring 34. As in the case of the spider previously described, I prefer to retain this disk in place against the spring pressure behind it by means of a spring-wire ring 35 fitting in a groove in a shoulder 36 of the operating disk l5. A pinl 37 projectingeccentrically from the disk 33 is pressed against the lever 24 by a spring 38, which operates in substantially the sameway as does the spring 28 shown` in Fig. 2.

In operation, the condenser or other piece of apparatus to'which my device is attached, is given a coarse adjustment by turning the operating disk 15 to the approximate location desired. This moves the shaft 14 and its carried -parts through the same angle as the disk 15. By reason of its connection with the operating disk l5, the spider 25 or springbacked disk 33 is rotated therewith and slid on the face of the panel board 11. 'When it is desired to obtain a fine adjustment, the knob 18 is turned. This rotation of the knob 18 turns the cam 21, whichV is, rigid therewith, and the cam 21 causes a'slight rotation of the cam follower 22 and the lever 24 about the axis of the shaft 23. Due to the fact that it is pressed against the stationary panel board ll, the spider 25 or springbaeked disk 33 now remains stationary, and so provides a stationary fulcrum` for the outer end of the lever 24, which results in a movement of the shaft 23 about the shaft 14. As the shaft 23 is carried by the disk 15, there results a turning of such disk and of the shaft 14 and its -carried parts, but through a very slight angle compared to that through which the knob moves. By varying the pitch of the cam and the length of the cam follower 22 and lever 24, I can lobtain any desired ratio of angular velocities between the shaft 14 and theiknob 18.

I claim as my invention:

l. In combination, an operating shaft for an adjustable device. an adjusting member fixed on said shaft for adjustingit, a second adjusting member co-axial with said l first adjusting member and rotatable relatively thereto, a cam operatedvby said seeond adjust-ing member, and means co-operating with said cam when said second adjusting member is rot-ated to cause rotation of said operating shaft through a smaller angle than that through which said second adjusting member is turned.

2. In combination, an operating shaft for an adjustable device, an adjusting member for adjusting said shaft, a second adjusting member co-axial with said first adjusting member and rotatable relatively thereto, a cam operated by said second adjusting member, and means co-operating with said cam when said second adjustin member is rotated to cause rotation o said operating shaft.

3. In combination, an operating shaft for an adjustable device, an adjusting member fixed or.- said shaftfor adjusting it, al second adjusting member co-aXial with said first adjusting member and rotatable relatively thereto, said second adjusting member being provided with a cam, and means operated by said cam upon the rotation of said second adjusting member to cause rotation of said operating shaft through a smaller angle than that through which said second adjusting member is turned.

4. In combination, an operating shaft for an adjustable device, an adjusting member for adjusting said shaft, a second adjusting member co-axial with said first adjusting member and rotatable relatively thereto, said second adjusting member provided with a cam, and means operated by said cam upon the rotation of said second adjusting member to cause rotation of said operating shaft.

5. In combination, an operating shaft for an adjustable device, a member fixed to saidy shaft for adjustingit, a second adjusting member co-aXial with said shaft and ca able of rotation relative thereto, said secon adj usting member being provided with a spiral cam, and a bell-crank pivoted on said first adjusting member and having one of its arms arranged to engage said cam, and means tending to hold stationary the end of the other arm of said bell-crank.

6. In combination, an operating shaft for an adjustable device, a stationary member, an adjusting member fixed on said shaft, a secon adjusting member co-axial with said shaft and capable of rotation relative thereto, said second adjusting member being provided with a cam, a member carried by said first adjusting member and spring-pressed against said stationary member, and means operated by said cam to cause relative rotation of said first adjusting member and said spring-pressed member when said second adjusting member is turned relative to said first adjusting member. 7. In combination, an operating shaft for an adjustable device, a stationary member,

an adjusting member fixed on said shaft, a second adjusting member co-axial with sa1d shaft andcapable of rotation relative thereto, said second adjustin member being provided with a cam, a ell-crank piVotally mounted on said rst adjusting member and having one of its arms arranged to bear against said cam, a member carried by said rst adjusting member and sprin -pressed against said stationary member, sai springpressed member havino a part engaging that arm of said bell-cranl; not bearing against said cam, and a spring acting between said first adjusting member and said springpressed member to insure engagement of said bell-crank with said cam.

8. In combination, an operating shaft for an adjustable device, two adjusting devices co-axial with each other, and cam means operated by one of said adjustingdevices' for adjusting said shaft circumferentiall at a reduced angular speed relative to t at vof such adjusting device.

9. In combination, an operating shaft for an adjustable device, two adjusting devices co-axial with each other, each of said adjusting devices having an operating member, and cam-operated means operated by one of said operating members and acting between the other operating member and a stationary member to move said shaft circumferentially. at a reduced circumferential s eed relative to that of such operating mem er.

10. In combination, an operating shaft for an adjustable device, an adjusting member co-axial therewith, a rotatable member adapted to have a frictional bearing on a stationary member, and cam-operated means operated by said adjusting member and acting between said rotatable member and said shaft to adjust the latter circumferentially at a reduced angular speed relative to that of said adjusting member.

11. In combinationz an operatin shaft for an adjustable device, two adjusting devices co-axial with each other, a rotatable member adapted to have a frictional bearing on a statlonary member, a cam operated by one of said operating members, means operated by said cam and acting between the other operating member and said rotatable member to drive said shaft at a reduced speed relative to that of the adjusting member which operates said cam.

12. In combination, an operating shaft for an adjustable device, a member fixed to said shaft for adjusting it, a second adjusting member co-axial with said shaft and ca able of rotation relative thereto, said secon adjusting member being provided with a spiral cam, and a bell-crank pivoted on said first adjustin member and having one of its arms arrange to engage said cam, and a member having a frictional drag on its movements tending to hold it stationary, said member being arranged to provide a fulcrum at the end of the other arm of said bell-crank.

13. Mechanism for adjusting a movable element in relation to a xed element primaril by an approximate adjustment and then y a Vernier adjustment, comprising a driving member, means carried thereby for indirectly coupling said driving member to the movable element during the a proximate adjustment of the latter, a lever p ate adapted to be rotated by said means during such adjustment, a friction plate mounted to rotate with said lever plate during the approximate adjustment, but to remain stationary and act as a fulcrum for said lever plate for the Vernier adjust-ment of the movable element.

14. Mechanism for adjusting a movable element in relation t" a fixed element including a driving member adapted to move the movable element therewith to give an approximate ad'ustmentof the latter with relation to the xed element, and means, on the reversal of the drlving element, for automatically Varying the leverage between said driving and movable elements, so that relatively arge movement of the driving element causes relatively small movement of the movable element.

15. Mechanism for adjusting a movable element in relation to a fixed element primaril by an approximate adjustment and then y a Vernier adjustment, comprising a lever plate adapted to be coupled with the movable element, a friction plate, means for coupling said friction plate to and moving it with the lever plate during the approximate adjustment and for causing it to remain stationary and act as a fulcrum to said lever plate during the Vernier adjustment, and lever plate operating means rotatable in one direction to bring into play said approximate adjustment and in the o posite direction to bring into play the Vernier adjustment.

16. Mechanism for adjusting a movable element in relation to a xed element primaril by an approximate adjustment and then y a Vernier adjustment, comprising a lever plate adapted to be coupled with the movab e element, a friction plate, means for cou ling said friction plate to and moving it wit the lever late during the approximate adjustment and) for causing it to remain stationary and act as a fulcrum to said lever plate during the Vernier adjustment, and

ever plate operating means rotatable in one direct-ion to bring into play said coarse ad- 'ustment and in the opposite direction to ring into play said Vernier adjustment, said operating means comprising the usual operating knob or handle with which the mechanism is provided.

17. Mechanism for adjusting a movable element in relation to a fixed element primarily by an approximate adjustment and then by a Vernier adjustment, comprising a lever plate adapted to be coupled with the movable element, a friction plate, means for coupling said friction plate to and moving it with the lever plate'during the approximate adjustment and for causing it to remain stationary and act as a fulcrum for said lever plate during the Vernier adjustment, lever plate operating means rotatable in one direction to brin into play said coarse adjustment and in t e opposite direction to bring into play said Vernier adjustment, said operating means comprising the usual operating knob or handle with which the mechanism is provided, and whereb either a forward or backward Vernier a justment may be effected at will. A

18. A Vernier for a rotatably adjustable shaft comprising, in combination, a unitary manually movable control 'means for obtaining both coarse and fine adjustment of said shaft, a rigid element rigidly connected to said shaft and having dial markings thereon /for indicating the amount of movement of saidshaft, coupling elements carried directly by said control means and said rigid element respectively and effective through one range of movement of said control means to directly connect said control means and said rigid element for movement of the latter by the former, and movement-transmitting means between said control means and said rigid element effective only through another range of movement from the control means to transmit movement from the control means to said rigid element at a reduced ratio 0r extent of movement of the latter, said direct connecting means operating wholly independently of said motion reduc- 40 tion means.

19. A Vernier for a rotatably adjustable shaft comprising, in combination, a unitary control means manually movable about ani axis concentric with said shaft for obtaining both coarse and fine adjustment thereof, a dial member for measuring the movement of said shaft, means forming a rigid connection between said shaft and said dial member, said control means and said dial memrect connection there-between upon movement of said control means in either direction beyond said limited arc for coarse adjustments, and means permitting a differential movement of said shaft relative to said control means for the fine adjustments, said differential means including a crank revolving about an axis parallel to said shaft and having an Operative bearing on said dial member turning the same about its axis, a

friction element for maintaining a fixed po 65 sition for the free end of the crank throughout the differential movement, and means operated by movement of said control means in its said limited arc for turning said crank.

In witness whereof, I havehereuntoset my hand at Indianapolis, Indiana, this 15th day of November, A. D. one thousand nine hundred and twenty-two. CHARLES R. BUTLER. 

